Bio-ethanol is an alternative fuel to gasoline that can be obtained by conversion of sugars, starch, and various lignocellulosic biomass such as woods, herbaceous crops, agricultural residues, waste paper, and other fractions of municipal solid waste. Lignocellulosic materials contain cellulose and hemicellulose that are bound together by lignin, and both cellulose and hemicellulose are polymers built up by long chains of sugar monomers. After pretreatment and hydrolysis these sugars can be converted into ethanol by fermentation. During hydrolysis of lignocellulosic materials with water or dilute acid under high temperature, lignin phenol monomers, such as 4-propyl-2-methoxyphenol (PMP), are often created from the hydrolysis of lignin and can inhibit the desired fermentation of monosaccharides into ethanol. Removal of inhibitors can, therefore, increase significantly the yield of bio-ethanol. Unfortunately, such selective inhibitor removal is limited by a lack of available separation techniques. Due to the high boiling point, larger molecular size, and low concentration of PMP, as well as strong interaction between enzyme and PMP, it is difficult to remove PMP from the hydrolysis solution via conventional technologies. Moreover, selectivity is a key need, since removal of PMP shouldn't cause loss of useful components such as sugar, other oligo- and mono-saccharides, and ethanol in the hydrolyzed solution. Thus, an engineered sorption technology with high selectivity is needed.
Besides this biotechnological application, phenolic compounds such as phenol, chlorophenol, etc. also exist in many industrial effluents such as those from oil refineries, coal processing, pharmaceutical, plastics, paint, leather, paper pulp, and steel industries. These recalcitrant and non-biodegradable organics accumulate in water and may contaminate underground sources irreversibly. The continuous consumption of water containing organic contaminant in excess of a few parts per billion (ppb) could lead to serious health problems depending on the type of the pollutant. Phenol can be easily absorbed through respiratory organ, skin, and alimentary canal of human being, is highly toxic to albumen, liver and nephridium, and can restrain also the central neural system. And chlorophenols may be carcinogenic. Therefore, separation and recovery of phenolic compounds from waste is often important for environmental protection, industrial safety, and process economics.
Accordingly, what is needed are sorbents and sorbent processes which are useful to separate low levels of contaminants from a fluid stream. It would further be desirable if such sorbents and processes could accommodate a solute favorably while allowing subsequent desorption without destruction of the sorbent. It would further be advantageous if such sorbents were useful to separate methoxyphenols in a hydrolyzed solution of biomass with good sorption selectivity.
Advantageously, sorbents and sorbent processes which are useful to separate low levels of contaminants from a fluid stream have been discovered. The sorbents and processes can accommodate a solute favorably while allowing subsequent desorption without destruction of the sorbent. The sorbents are useful to separate, for example, methoxyphenols in a hydrolyzed solution of biomass with good sorption selectivity.
In one embodiment the invention pertains to a composition comprising a functionalized poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate). The instant functionalized poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate) polymers are unlike those functionalized with an aliphatic amine such as described at, for example, M. Walenius and P. Flodin, “Reaction of the epoxide groups of the copolymer trimethylolpropane trimethacrylate-glycidyl methacrylate with aliphatic amino compounds”, Br. Polym. J., 23 (1990) 67. Instead, the instant invention comprises poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate) functionalized with a non-aliphatic amine compound such as one having the structure NH2—R1OH wherein R1 is a substituted or unsubstituted phenylene.
In another embodiment, the instant invention pertains to a method of reducing the amount of one or more low level contaminants of a fluid stream. The method comprises contacting the fluid stream comprising an initial concentration of one or more low level contaminants with one or more suitably functionalized poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate) sorbents. The contacting is conducted in a manner such that the initial concentration of one or more low level contaminants in the fluid stream is reduced by sorption of said one or more low level contaminants on said sorbent. The process next comprises desorbing one or more functionalized poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate) sorbents by passing a regenerating fluid over said sorbents.